LONDON (Agence de Presse Medicale for Reuters Health) - Britain's Microscience said on Tuesday that a phase I study in 30 healthy volunteers showed its oral hepatitis vaccine, spi-VEC, had an excellent safety profile and was highly immunogenic.

The vaccine consists of harmless Salmonella bacteria that have been modified to carry a hepatitis B antigen.

"After two doses all of the subjects mounted a cellular immune response against the vaccine antigen," the company said in a statement.

"Moreover, in over 90% of the subjects, the type of immune response was characterised by the production of gamma interferon, known to be important in promoting clearance of the hepatitis B virus."

Microscience said it would now start phase ll trials to see whether the vaccine helps patients who are chronically infected with hepatitis B.